Preparation method of ruthenium molybdenum manganese composite electrocatalyst for purifying chlorine-containing organic waste gas

Abstract

The invention relates to the technical field of composite electrocatalysts, in particular to a preparation method of a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas, which comprises the following steps: S1, dissolving ruthenium salt and manganese salt in deionized water according to a certain proportion, and stirring for a period of time to obtain a mixed solution; s2, introducing a certain amount of ozone gas into the mixed solution prepared in S1; s3, weighing a certain amount of phosphomolybdic acid, adding the phosphomolybdic acid into the mixed solution in S2, and continuously stirring for a period of time to obtain a stable solid precipitate; and S4, putting the solid precipitate prepared in S3 into a muffle furnace, and roasting at a certain temperature to obtain the ruthenium-molybdenum-manganese composite electrocatalyst. By optimizing the loading proportion of ruthenium, molybdenum and manganese and the preparation method, the stability and catalytic activity of the catalyst are effectively improved. The catalyst has excellent chlorine poisoning resistance, can efficiently decompose chlorine-containing VOCs at a low temperature, realizes rapid dissociation of chlorine atoms and organic groups, and inhibits generation of by-products.

Description

Technical Field

[0001] The invention relates to the technical field of composite electrocatalysts, and in particular to a method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas. Background Art

[0002] Against the backdrop of rapid industrial development, the emission of volatile organic compounds (VOCs) has become increasingly prominent, especially the accumulation of chlorinated organic compounds (Cl-VOCs) in the environment, which poses a serious threat to the ecosystem and human health. Cl-VOCs are widely used in chemical, pharmaceutical, coating and other industrial fields, but because of the presence of chlorine in its chemical structure, toxic byproducts such as chlorinated dioxins and hydrogen chloride are easily generated during the emission process, which are extremely harmful to the environment and human body. In addition, the degradation of Cl-VOCs is difficult, and traditional waste gas treatment processes such as combustion, adsorption and catalytic oxidation are subject to many restrictions in the treatment of chlorine-containing waste gas due to high energy consumption, incomplete treatment or the generation of by-products.

[0003] Among the existing Cl-VOCs treatment technologies, catalytic oxidation technology has gradually attracted attention. Among them, electrocatalytic oxidation can not only treat toxic and harmful gases at a lower temperature, but also avoid secondary pollutants generated by high-temperature incineration. However, the treatment of Cl-VOCs faces many technical difficulties. For example, the chlorine groups in Cl-VOCs can easily cause catalyst poisoning and deactivation in the catalytic reaction, reducing the service life of the catalyst. Under low oxygen conditions, the decomposition and complete oxidation of Cl-VOCs are difficult to achieve. How to improve the activity of the catalyst is a technical problem that needs to be solved urgently in the current catalytic field.

[0004] Therefore, in order to solve the above technical problems, the present application proposes a method for preparing a ruthenium, molybdenum and manganese composite electrocatalyst for purifying chlorine-containing organic waste gas. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and propose a method for preparing a ruthenium, molybdenum and manganese composite electrocatalyst for purifying chlorine-containing organic waste gas. The synergistic effect of ruthenium, molybdenum and manganese is combined, and the metal loading ratio and the microstructure of the catalyst are controlled so that the prepared composite catalyst can effectively catalyze the degradation reaction of Cl-VOCs at low temperature.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a ruthenium, molybdenum and manganese composite electrocatalyst for purifying chlorine-containing organic waste gas, the specific steps are as follows:

[0008] S1. Dissolve a certain proportion of ruthenium salt and manganese salt in deionized water and stir for a period of time to obtain a mixed solution;

[0009] S2, introducing a certain amount of ozone gas into the mixed solution prepared in S1;

[0010] S3, weigh a certain amount of phosphomolybdic acid and add it to the mixed solution of S2, continue stirring for a period of time to obtain a stable solid precipitate;

[0011] S4. The solid precipitate obtained in S3 is placed in a muffle furnace and calcined at a certain temperature to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0012] Preferably, in step S1, the ruthenium salt is a mixture of one or more of ruthenium chloride, ruthenium nitrate and ruthenium sulfate; the manganese salt is a mixture of one or more of manganese nitrate, manganese chloride and manganese sulfate.

[0013] Preferably, in step S1, the molar ratio of ruthenium element to manganese element in the ruthenium salt and the manganese salt is 0.005:1 to 0.05:1, and the stirring time is 10 to 60 minutes.

[0014] Preferably, in step S2, the ozone gas is introduced at a rate of 10 to 100 mL / min, an ozone concentration of 20 to 100 mg / L, and a ventilation time of 10 to 120 min.

[0015] Preferably, in step S3, the phosphomolybdic acid is 1wt% to 10wt% of the amount of manganese element added, and the stirring time is 30 to 120 min.

[0016] Preferably, in step S4, the calcination temperature is 300-600° C., the heating rate is 1-10° C. / min, and the calcination time is 1-10 h.

[0017] By adopting the above technical scheme: Here, the loading ratio and preparation process of the three metals of ruthenium (Ru), molybdenum (Mo), and manganese (Mn) are optimized to improve the degradation efficiency of Cl-VOCs and the ability to resist chlorine poisoning. Among them, ruthenium, molybdenum, and manganese each have unique catalytic properties and synergistic chemical properties, so that the composite electrocatalyst can work efficiently in an ultra-low oxygen environment. Ruthenium has excellent redox properties and can promote the activation and decomposition of Cl-VOCs in electrocatalysis; molybdenum acts as a stabilizer and structure regulator in the catalyst, which can improve the durability and anti-poisoning of the catalyst; manganese accelerates the catalytic reaction by enhancing the number of surface active sites, especially has a significant promoting effect on the dissociation of chlorine atoms. The design of this composite electrocatalyst combines the synergistic effects of ruthenium, molybdenum, and manganese. By controlling the metal loading ratio and the microstructure of the catalyst, the catalyst can effectively catalyze the degradation reaction of Cl-VOCs at low temperatures.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. Compared with traditional catalysts, the ruthenium-molybdenum-manganese composite electrocatalyst of the present invention is more stable in a chlorine-containing environment, can maintain high activity under long-term operation, and avoids the problem of catalyst deactivation caused by chloride accumulation.

[0020] 2. The catalyst of the present invention can achieve efficient decomposition of chlorine-containing organic matter at a relatively low reaction temperature, thus reducing the demand for energy consumption.

[0021] 3. The catalyst of the present invention has excellent purification ability. Its high efficiency and low temperature characteristics meet the requirements of green environmental protection, help reduce industrial chlorine-containing VOCs emissions, and alleviate environmental pollution pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the XRD pattern of the composite catalyst prepared in Example 1 of the present invention;

[0023] Figure 2 This is a continuous long-term catalytic test diagram of the electrocatalyst prepared in Example 1 of the present invention for chlorobenzene. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0025] Embodiment 1:

[0026] (1) Dissolve 0.1 mmol of ruthenium nitrate and 10 mmol of manganese nitrate in 40 mL of deionized water and stir for 30 min;

[0027] (2) Add ozone gas at a concentration of 50 mg / L into the solution at 50 mL / min for 60 min;

[0028] (3) adding phosphomolybdic acid (5 wt % of manganese) and stirring for 60 min to obtain a precipitate;

[0029] (4) The precipitate is heated to 450°C in a muffle furnace at a heating rate of 5°C / min and calcined for 5 hours to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0030] The XRD pattern of the catalyst prepared in Example 1 is as follows: Figure 1 As shown in the figure, it can be seen that RuO2, MoO3 and MnOx The characteristic peaks of the composite material indicate that RuO2, MoO3 and MnO x Take 1g of the catalyst prepared in Example 1 and heat it at a reaction space velocity of 12000mL·h -1 , chlorobenzene concentration is 1000mg / m 3 and 5.5A current conditions for electrocatalytic oxidation, such as Figure 2 As shown in the figure, the chlorobenzene removal efficiency reached 95% at 120°C and its stability was still good after 12 hours of continuous testing. However, there was no chlorobenzene removal effect when no electricity was applied, indicating that the prepared composite catalyst can show excellent electrothermal removal activity for chlorinated VOCs.

[0031] Embodiment 2:

[0032] (1) Dissolve 0.05 mmol of ruthenium chloride, 5 mmol of manganese nitrate and 5 mmol of manganese chloride in 25 mL of deionized water and stir for 60 min;

[0033] (2) Add ozone gas at a concentration of 30 mg / L at 70 mL / min into the solution for 30 min;

[0034] (3) adding phosphomolybdic acid (3 wt % of manganese) and stirring for 45 min to obtain a precipitate;

[0035] (4) The precipitate is heated to 600°C at a heating rate of 1°C / min and calcined for 2 hours to obtain the desired ruthenium, molybdenum and manganese composite electrocatalyst.

[0036] 1 g of the catalyst prepared in Example 2 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 85% at 120°C and the stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show excellent electrothermal removal activity of chlorine-containing VOCs.

[0037] Embodiment 3:

[0038] (1) Dissolve 0.5 mmol of ruthenium nitrate, 2 mmol of manganese sulfate, 3 mmol of manganese nitrate and 5 mmol of manganese chloride in 55 mL of deionized water and stir for 45 min;

[0039] (2) Introduce ozone gas at 40 mL / min, concentration of 80 mg / L, for 45 min;

[0040] (3) adding phosphomolybdic acid (4 wt % of manganese) and stirring for 60 min to obtain a precipitate;

[0041] (4) The precipitate is heated to 500°C at a heating rate of 2°C / min and calcined for 8 h to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0042] 1 g of the catalyst prepared in Example 3 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 79% at 120°C and its stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can exhibit excellent electrothermal removal activity for chlorine-containing VOCs.

[0043] Example 4

[0044] (1) Dissolve 0.15 mmol g of ruthenium chloride and 10 mmol of manganese chloride in 50 mL of deionized water and stir for 20 min;

[0045] (2) Add ozone gas at a concentration of 60 mg / L at 80 mL / min for 20 min;

[0046] (3) adding phosphomolybdic acid (8 wt % of manganese) and stirring for 30 min to obtain a precipitate;

[0047] (4) The precipitate is heated to 450°C at a heating rate of 3°C / min and calcined for 9 h to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0048] 1 g of the catalyst prepared in Example 4 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 80% at 120°C and its stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show excellent electrothermal removal activity of chlorine-containing VOCs.

[0049] Example 5

[0050] (1) Dissolve 0.1 mmol of ruthenium nitrate, 0.1 mmol of ruthenium chloride, and 10 mmol of manganese nitrate in 30 mL of deionized water and stir for 40 min;

[0051] (2) Introduce ozone gas at a concentration of 40 mg / L at 30 mL / min for 90 min;

[0052] (3) adding phosphomolybdic acid (6 wt % of manganese) and stirring for 90 min to obtain a precipitate;

[0053] (4) The precipitate is calcined at a temperature of 550°C at a heating rate of 4°C / min for 6 hours to prepare a ruthenium-molybdenum-manganese composite electrocatalyst.

[0054] 1 g of the catalyst prepared in Example 5 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 77% at 120°C and its stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show excellent electrothermal removal activity of chlorine-containing VOCs.

[0055] Example 6

[0056] (1) Dissolve 0.15 mmol of ruthenium chloride, 0.1 mmol of rhodium sulfate, and 10 mmol of manganese nitrate in 30 mL of deionized water and stir for 25 min;

[0057] (2) Add ozone gas at a concentration of 25 mg / L at 90 mL / min for 45 min;

[0058] (3) adding phosphomolybdic acid (7 wt % of manganese) and stirring for 40 min to obtain a precipitate;

[0059] (4) The precipitate is calcined at a temperature of 550° C. at a heating rate of 6° C. / min for 7 hours to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0060] 1 g of the catalyst prepared in Example 6 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 88% at 120°C and the stability was still good after 12 hours of continuous testing, indicating that the prepared composite catalyst can exhibit excellent electrothermal removal activity for chlorine-containing VOCs.

[0061] Example 7

[0062] (1) Dissolve 0.3 mmol of ruthenium sulfate and 10 mmol of manganese nitrate in 60 mL of deionized water and stir for 35 min;

[0063] (2) Add ozone gas at a concentration of 50 mg / L at 60 mL / min for 30 min;

[0064] (3) adding phosphomolybdic acid (9 wt % of manganese) and stirring for 70 min to obtain a precipitate;

[0065] (4) The precipitate was heated to 600° C. at a heating rate of 7° C. / min and calcined for 4 hours to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0066] 1 g of the catalyst prepared in Example 7 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 76% at 120°C and its stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show excellent electrothermal removal activity of chlorine-containing VOCs.

[0067] Example 8

[0068] (1) Dissolve 0.05 mmol of ruthenium chloride, 0.1 mmol of rhodium nitrate, 0.1 mmol of rhodium sulfate and 10 mmol of manganese nitrate in 45 mL of deionized water and stir for 20 min;

[0069] (2) Add ozone gas at a concentration of 70 mg / L at 50 mL / min for 20 min;

[0070] (3) adding phosphomolybdic acid (2 wt % of manganese) and stirring for 90 min to obtain a precipitate;

[0071] (4) The precipitate is heated to 470°C at a heating rate of 8°C / min and calcined for 3 h to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0072] 1 g of the catalyst prepared in Example 8 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 74% at 120°C and the stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show excellent electrothermal removal activity of chlorine-containing VOCs.

[0073] Example 9

[0074] (1) Dissolve 0.4 mmol of ruthenium nitrate and 10 mmol of manganese sulfate in 100 mL of deionized water and stir for 25 min;

[0075] (2) Introduce ozone gas at a rate of 100 mL / min, with a concentration of 100 mg / L, for 10 min;

[0076] (3) adding phosphomolybdic acid (10 wt % of manganese) and stirring for 50 min to obtain a precipitate;

[0077] (4) The precipitate is heated to 300°C at a heating rate of 9°C / min and calcined for 10 h to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0078] 1 g of the catalyst prepared in Example 9 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 70% at 120°C and its stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show relatively excellent electrothermal removal activity of chlorine-containing VOCs.

[0079] Example 10

[0080] (1) Dissolve 0.45 mmol of ruthenium nitrate and 10 mmol of manganese chloride in 90 mL of deionized water and stir for 10 min;

[0081] (2) Introduce ozone gas at a concentration of 90 mg / L at 10 mL / min for 120 min;

[0082] (3) adding phosphomolybdic acid (1 wt% of manganese) and stirring for 120 min to obtain a precipitate;

[0083] (4) The precipitate is heated to 600°C at a heating rate of 10°C / min and calcined for 1 h to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

[0084] 1 g of the catalyst prepared in Example 10 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. The chlorobenzene removal efficiency reached 81% at 120°C and the stability was still good after 12h continuous testing, indicating that the prepared composite catalyst can show excellent electrothermal removal activity of chlorine-containing VOCs.

[0085] Comparative Example 1

[0086] (1) Dissolve 0.1 mmol of ruthenium nitrate and 10 mmol of manganese oxide in 20 mL of deionized water and stir for 30 minutes;

[0087] (2) without introducing ozone gas, phosphomolybdic acid (5 wt % of manganese) was directly added and stirred for 60 min to obtain a precipitate;

[0088] (3) The precipitate was calcined at 500°C for 5 h to obtain a control catalyst.

[0089] 1 g of the catalyst prepared in Example 1 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 and 5.5A current conditions for electrocatalytic oxidation, such as Figure 2 As shown, it is non-conductive at 120°C and has no catalytic activity for chlorobenzene.

[0090] Comparative Example 2

[0091] (1) Dissolve 0.1 mmol of ruthenium nitrate and 10 mmol of manganese nitrate in 20 mL of deionized water and stir for 30 min;

[0092] (2) Add ozone gas at a concentration of 50 mg / L at 50 mL / min into the solution for 60 min;

[0093] (3) Without adding phosphomolybdic acid, the above precipitate was directly calcined at 500° C. for 5 h to obtain a control catalyst.

[0094] 1 g of the catalyst prepared in Example 2 was used at a reaction space velocity of 12000 mL·h -1 , chlorobenzene concentration is 1000mg / m 3 The electrocatalytic oxidation was carried out under the conditions of 5.5A current. Although there was 30% catalytic activity of chlorobenzene at 120℃, the catalyst was quickly deactivated.

[0095] The performance test results of the above-mentioned embodiments 1-10 and comparative examples 1-2 are shown in Table 1.

[0096] Table 1 shows the performance test results of various implementation examples and control examples

[0097]

[0098] In summary, the preparation process of the present invention is simple and easy to realize industrial production. Through the optimization of the load ratio and the innovation of the preparation method, the catalyst can adapt to high flow and long-term working requirements in practical applications. The successful development of this catalyst not only provides a new method for the efficient treatment of chlorine-containing waste gas, but also effectively fills the technical gap in the field of electrocatalytic degradation of Cl-VOCs under ultra-low oxygen conditions. It has high practicality and promotion value. Through the promotion of this technology, the emission of chlorine-containing pollutants in the atmosphere can be effectively reduced, the improvement of the ecological environment can be promoted, and the country's low-carbon environmental protection strategy can be promoted.

[0099] The description and practice disclosed in the present invention are easy to think and understand for ordinary technicians in the technical field, and several improvements and modifications can be made without departing from the principles of the present invention. Therefore, modifications or improvements made without departing from the spirit of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas, characterized in that: The specific steps are as follows: S1. Dissolve a certain proportion of ruthenium salt and manganese salt in deionized water and stir for a period of time to obtain a mixed solution; S2, introducing a certain amount of ozone gas into the mixed solution prepared in S1; S3, weigh a certain amount of phosphomolybdic acid and add it to the mixed solution of S2, continue stirring for a period of time to obtain a stable solid precipitate; S4. The solid precipitate obtained in S3 is placed in a muffle furnace and calcined at a certain temperature to obtain a ruthenium-molybdenum-manganese composite electrocatalyst.

2. The method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas according to claim 1, characterized in that: In step S1, the ruthenium salt is a mixture of one or more of ruthenium chloride, ruthenium nitrate, and ruthenium sulfate; the manganese salt is a mixture of one or more of manganese nitrate, manganese chloride, and manganese sulfate.

3. The method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas according to claim 1, characterized in that: In step S1, the molar ratio of ruthenium element to manganese element in the ruthenium salt and the manganese salt is 0.005:1 to 0.05:1, and the stirring time is 10 to 60 minutes.

4. The method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas according to claim 1, characterized in that: In step S2, the ozone gas is introduced at a rate of 10 to 100 mL / min, an ozone concentration of 20 to 100 mg / L, and a ventilation time of 10 to 120 min.

5. The method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas according to claim 3, characterized in that: In step S3, the phosphomolybdic acid is 1wt% to 10wt% of the manganese element dosage, and the stirring time is 30 to 120 min.

6. The method for preparing a ruthenium-molybdenum-manganese composite electrocatalyst for purifying chlorine-containing organic waste gas according to claim 1, characterized in that: In step S4, the calcination temperature is 300-600° C., the heating rate is 1-10° C. / min, and the calcination time is 1-10 h.

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